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Cell Discovery

Springer Science and Business Media LLC

Preprints posted in the last 7 days, ranked by how well they match Cell Discovery's content profile, based on 54 papers previously published here. The average preprint has a 0.22% match score for this journal, so anything above that is already an above-average fit.

1
Efficient generation of epitope-targeted de novo antibodies with Germinal

Mille-Fragoso, L. S.; Driscoll, C. L.; Wang, J. N.; Dai, H.; Widatalla, T. M.; Zhang, J. L.; Zhang, X.; Rao, B.; Feng, L.; Hie, B. L.; Gao, X. J.

2026-04-15 synthetic biology 10.1101/2025.09.19.677421 medRxiv
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Obtaining novel antibodies against specific protein targets is a widely important yet experimentally laborious process. Meanwhile, computational methods for antibody design have been limited by low success rates that currently require resource-intensive screening. Here, we introduce Germinal, a broadly enabling generative pipeline that designs antibodies against specific epitopes with nanomolar binding affinities while requiring only low-n experimental testing. Our method co-optimizes antibody structure and sequence by integrating a structure predictor with an antibody-specific protein language model to perform de novo design of functional complementarity-determining regions (CDRs) onto a user-specified structural framework. When tested against four diverse protein targets, Germinal successfully designed functional antibodies across all targets and binder formats, testing only 43-101 designs for each antigen. Validated designs also exhibited robust expression in mammalian cells and high sequence and structural novelty. We provide open-source code and full computational and experimental protocols to facilitate wide adoption. Germinal represents a milestone in efficient, epitope-targeted de novo antibody design, with notable implications for the development of molecular tools and therapeutics.

2
De novo designed bifunctional proteins for targeted protein degradation

Mylemans, B.; Korona, B.; Acevedo-Jake, A. M.; MacRae, A.; Edwards, T. A.; Huang, D. T.; Wilson, A. J.; Itzhaki, L. S.; Woolfson, D. N.

2026-04-15 synthetic biology 10.64898/2025.12.22.695915 medRxiv
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Targeted protein degradation (TPD) is a therapeutic strategy to remove disease-causing proteins by routing them to the ubiquitin-proteasome, autophagy, or lysosme machineries. For instance, proteolysis-targeting chimeras (PROTACs) are synthetic hetero-bifunctional small molecules that simultaneously bind the target and an E3 ubiquitin ligase to drive ubiquitination and degradation by the proteasome. Despite considerable success, designing such molecules is challenging and the number of currently addressable ubiquitin E3 ligases is limited. Here we demonstrate hetero-bifunctional de novo designed proteins as alternatives for TPD to access more targets and ligases. First, we develop a stable and highly adaptable helix-turn-helix scaffold for presenting different binding sites. Next, we use computational protein design to incorporate and embellish hot-spot- binding sites to target BCL-xL, plus short linear motifs (SLiMs) for KLHL20 ligase recruitment. The resulting mono- and bi-functionalised proteins bind the targets in vitro, and the latter degrade BCL-xL in cells leading to apoptosis.

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The Evolutionary Dynamics and Regional Spread of Mpox in Africa: Insights from Multi-country Genomic Surveillance

Tanui, C. K.; Kinganda-Lusamaki, E.; O'Toole, A.; Chitenje, M.; Campbell, A. K. O.; DIAGNE, M. M.; Kanyerezi, S.; Faye, M.; Ifabumuyi, S. O.; Nzoyikorera, N.; Lango, H. O.; Koukouikila-Koussounda, F.; Meite, S.; Sikazwe, E.; Djuicy, D. D.; Adu, B.; MAMAN, I.; Mapunda, L. A.; Nyan, D. C.; Stephane, S.; Aricha, S. A.; Cherif Gnimadi, T. A.; Maror, J. A.; Pereira, A. M.; Atrah, Y. S.; Akanbi, O. A.; Lokilo, E. L.; Makangara-Cigolo, J.-C.; Paku, P. T.; Luakanda, G. N.; Amuri-Aziza, A.; Wawina-Bokalanga, T.; Mugerwa, I.; Nsawotebba, A.; Ayitewala, A.; Williams, A. J.; Folorunso, V.; Mani, S.; Hardi

2026-04-11 infectious diseases 10.64898/2026.04.07.26347884 medRxiv
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The recent MPXV epidemic across Africa revealed extensive viral diversity and complex transmission dynamics, prompting a continent-wide genomic investigation. We analysed 3,450 high-quality MPXV virus whole genomes from 24 African Union Member States, revealing the complex and concurrent circulation of Subclades Ia, Ib, IIa, and IIb. Subclade Ia showed high levels of virus diversity in reservoir hosts in Central Africa, detected through zoonotic transmission and some sustained human outbreak lastly detected. In contrast, Clade Ib exhibited signatures of sustained human to human transmission across Eastern and Southern Africa. Clade IIa remains largely zoonotic in West Africa. Like Ia, IIb shows continued zoonotic transmission, and sustained human outbreak linked to lineage G1 and G2 circulation. Phylogeographic analyses revealed frequent cross border transmission and interconnectedness, which was aligned with both human mobility corridors and international boundaries. For instance, the Democratic Republic of the Congo or Sierra Leone seems to emerge as a source of regional exportation, while the Cameroon and Nigeria, CAR and Cameroon or CAR and DRC interfaces reflected ongoing cross border zoonotic spillovers. These findings underscore the need for harmonised genomic surveillance, APOBEC3-aware triage, and integrated One Health strategies to prevent local outbreaks from escalating into regional epidemics and to inform vaccine deployment and public health preparedness.

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GPR143, a novel immunohistochemical marker for renal tumors with FLCN/TSC/MTOR-TFE alterations

Li, Q.; Singh, A.; Hu, R.; Huang, W.; Shapiro, D. D.; Abel, E. J.; Zong, Y.

2026-04-13 pathology 10.64898/2026.04.06.26350070 medRxiv
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Although several ancillary tests are available in limited laboratories, diagnosis of microphthalmia (MiT)/TFE family translocation renal cell carcinoma (tRCC) could be challenging due to diverse and overlapping tumor morphology and the lack of reliable biomarkers. GPNMB has been recently identified as a diagnostic marker for various renal neoplasms with FLCN/TSC/mTOR-TFE alterations. However, the sensitivity and specificity of GPNMB immunostain are suboptimal and the result interpretation in ambiguous cases could be difficult. To search additional biomarkers that could improve the screening sensitivity and predict genetic aberrations in FLCN/TSC/mTOR-TFE pathway in renal tumors, we performed bioinformatic analysis of publicly available cancer databases and found GPR143, a transmembrane protein regulated by MiT transcription factors, was highly expressed in a subset of renal cell carcinomas (RCCs). In two the Cancer Genome Atlas (TCGA) kidney cancer cohorts, RCCs with high levels of GPR143 expression were enriched for renal neoplasms with FLCN/TSC/mTOR-TFE alterations. Similar to GPNMB labeling, GPR143 immunostain was positive in the majority of tRCC cases and renal tumors with FLCN/TSC/mTOR alterations, suggesting that GPR143 could function as another surrogate marker for FLCN/TSC/mTOR-TFE alterations in certain renal tumors. Interestingly, despite the concordant GPR143 and GPNMB immunoreactivity in most renal neoplasms with FLCN/TSC/mTOR-TFE alterations, diffuse GPR143 immunostain was observed in some cases with negative or focal GPNMB labeling. Taken together, our results indicate GPR143 could serve as a useful adjunct marker to improve the sensitivity for screening renal tumors with FLCN/TSC/mTOR-TFE alterations.

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Drug response profiling guides precision therapy in relapsed and refractory childhood acute lymphoblastic leukemia

Steffen, F. D.; Lissat, A.; Alten, J.; Kriston, A.; Scheidegger, N.; Eckert, C.; Bodmer, N.; Schori, L.; Schühle, S.; Arpagaus, A.; Gutnik, S.; Manioti, D.; Bruderer, N.; Zeckanovic, A.; Västrik, I.; Nyiri, G.; Kovacs, F.; Thorhauge Als-Nielsen, B. E.; Attarbaschi, A.; Rademacher, A.; Elitzur, S.; Jacoby, E.; De Moerloose, B.; Svenberg, P.; Ancliff, P.; Sramkova, L.; Buldini, B.; Balduzzi, A.; Boer, J. M.; Mielcarek, M.; Ceppi, F.; Ansari, M.; Halter, J.; Schmiegelow, K.; Locatelli, F.; DelBufalo, F.; Stanulla, M.; Kulozik, A. E.; Schrappe, M.; Rohrlich, P.; Cave, H.; Baruchel, A.; von Stack

2026-04-11 oncology 10.64898/2026.04.08.26350164 medRxiv
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Children with relapsed or refractory acute lymphoblastic leukemia (ALL) require more effective and less toxic therapies. We established a prospective, multicenter Drug Response Profiling (DRP) registry (NCT06550102) integrating functional testing into precision-guided treatment. DRP was performed for 340 patients from 17 European countries with a turn-around time of two-weeks. Image-based drug screening with over 135000 unique perturbations revealed a heterogeneous landscape of ex vivo responses to 88 drugs on average. Ranking drug responses across the patient cohort defined individual drug fingerprints, identifying "DRP twins" by similarity in sensitivity and resistance independent of genetic ALL subtypes. Of 239 high-risk patients with follow-up, DRP-informed interventions were reported for 63 patients (26%). Patients received combination therapies based on venetoclax, tyrosine kinase inhibitors, trametinib, bortezomib or selinexor, resulting in objective clinical responses in 43 cases (68%). Precision-guided treatments allowed bridging to cellular therapies in 42 patients among whom 28 (67%) were still alive with a median follow-up of 21 months after DRP (IQR: 14.7-26.6 months). Top responders to venetoclax, ranked within the first tertile of the cohort, had superior 1-year event-survival compared to venetoclax non-responders (0.57 [95% CI, 0.39-0.85] vs. 0.25 [95% CI, 0.11-0.58]). Collectively, these findings demonstrate the feasibility and clinical relevance of functional profiling within an international network. This scalable framework enables individualized therapy selection for enrolment in adaptive precision trials for high-risk pediatric ALL.

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Identification, evolutionary history and characteristics of orphan genes in root-knot nematodes

Seckin, E.; Colinet, D.; Bailly-Bechet, M.; Seassau, A.; Bottini, S.; Sarti, E.; Danchin, E. G.

2026-04-11 bioinformatics 10.64898/2025.12.19.695360 medRxiv
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Orphan genes, lacking homologs in other species, are systematically found across genomes. Their presence may result from extensive divergence from pre-existing genes or from de novo gene birth, which occurs when a gene emerges from a previously non-genic region. In this study, we identified orphan genes in the genomes of globally distributed plant-parasitic nematodes of the genus Meloidogyne and investigated their origins, evolution, and characteristics. Using a comparative genomics framework across 85 nematode species, we found that 18% of Meloidogyne genes are genus-specific, transcriptionally supported orphans. By combining ancestral sequence reconstruction and synteny-based approaches, we inferred that 20% of these orphan genes originated through high divergence, while 18% likely emerged de novo. Proteomic and translatomic evidence confirmed the translation of a subset of these genes, and feature analyses revealed distinctive molecular signatures, including shorter length, signal peptide enrichment, and a tendency for extracellular localization. These findings highlight orphan genes as a substantial and previously underexplored component of the Meloidogyne genome, with potential roles in their worldwide parasitism.

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Transmission dynamics of the COVID-19 pandemic across the emerging variants in mainland China: a hypergraph-based spatiotemporal modeling study

Wang, Y.; WANG, D.; Lau, Y. C.; Du, Z.; Cowling, B. J.; Zhao, Y.; Ali, S. T.

2026-04-17 public and global health 10.64898/2026.04.16.26351004 medRxiv
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Mainland China experienced multiple waves of COVID19 pandemic during 2020 2022, driven by emerging variants and changes in public health and social measures (PHSMs). We developed a hypergraph-based Susceptible Vaccinated Exposed Infectious Recovered Susceptible (SVEIRS) model to reconstruct epidemic dynamics across 31 provinces, capturing transmission heterogeneity associated with clustered contacts. We assessed key characteristics of transmission at national and provincial levels during four outbreak periods: initial, localized predelta, Delta, and widespread Omicron, which accounted for 96.7% of all infections. We found significant diversity in transmission contributions across cluster sizes, with a small fraction of larger clusters responsible for a disproportionate share of infections. Counterfactual analyses showed that reducing clustersize heterogeneity, while holding overall exposure constant, could have lowered national infections by 11.70 to 30.79%, with the largest effects during Omicron period. Ascertainment rates increased over time but remained spatially heterogeneous with a range: (14.40, 71.93)%. Population susceptibility declined following mass vaccination (to 42.49% in Aug 2021, nationally) and rebounded (to 89.89% in Nov 2022) due to waning immunity with variations across the provinces. Effective reproduction numbers displayed marked temporal and spatial variability, with higher estimates during Omicron. Overall, these results highlight critical role of group contact heterogeneity in shaping epidemic dynamics.

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Integrated mapping of human meniscus and cartilage eQTLs reveals shared and distinct osteoarthritis genetic drivers

Uchida, Y.; Fujii, Y.; Swahn, H.; Ueda, M. T.; Chiba, T.; Matsushima, T.; Naito, Y.; Nakamichi, R.; Takahashi, K.; Olmer, M.; The RE-JOIN Consortium Investigators, ; Lotz, M.; Kochi, Y.; Asahara, H.

2026-04-16 orthopedics 10.64898/2026.04.12.26350702 medRxiv
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Osteoarthritis (OA) is a prevalent musculoskeletal disorder and a leading cause of global disability. Although meniscal damage is a major risk factor of OA pathogenesis, genetic regulatory studies have remained largely confined to articular cartilage. Here, we establish the first comprehensive expression quantitative trait locus (eQTL) map integrating whole-genome sequencing and bulk transcriptomics from human meniscus (n=112) and cartilage (n=113). Supported by single-nucleus multiomics (cartilage: 56,549 nuclei; meniscus: 34,343 nuclei), we uncovered highly tissue-specific genetic risk architectures. Colocalization with OA GWAS identified 27 meniscus-specific, 28 shared, and 20 cartilage-specific causal genes. Chromatin-informed fine-mapping and deconvolution elucidated distinct pathogenic mechanisms; notably, meniscus-specific signals converged on VEGFA via rare promoter variants and an enhancer in fibrochondrocyte progenitors, alongside a shared eQTL for CLEC18A. Exploratory analysis suggested candidate compounds to reverse pathogenic gene expression. Our findings underscore the meniscus as a distinct genetic driver, molecularly reinforcing OA as an entire joint organ failure.

9
A high-throughput Epstein-Barr virus nuclear antigen 1 (EBNA1) serology test strip for nasopharyngeal carcinoma risk screening

Warner, B. E.; Patel, J.; Satterwhite, R.; Wang, R.; Adams-Haduch, J.; Koh, W.-P.; Yuan, J.-M.; Shair, K. H. Y.

2026-04-13 infectious diseases 10.64898/2026.04.08.26350329 medRxiv
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PurposeAntibodies to Epstein-Barr virus (EBV) proteins can predict nasopharyngeal carcinoma (NPC) risk. We previously defined a prototype EBNA1 protein panel and multiplex immunoblot assay that distinguishes NPC risk several years pre-diagnosis. Assay throughput and specificity are critical to effectively implement a population-level screening program. Here, we developed a strip test assay - EBNA1 SeroStrip-HT - with an objective to increase throughput and maximize specificity. Experimental DesignEBNA1 full-length (FL) and glycine-alanine repeat deletion mutants (dGAr) were purified from insect and mammalian cells to screen serum IgA/IgG from prospective cohorts in Singapore and Shanghai, China, with known time intervals to NPC diagnosis. Twenty pre-diagnostic sera within 4 years to diagnosis were compared to 96 healthy controls using a nested case-control study design. ResultsIgA to mammalian-derived EBNA1 dGAr achieved 85.0% sensitivity and 94.8% specificity (AUC, 0.939) for NPC status. IgA to insect-derived EBNA1 dGAr showed the same sensitivity (85.0%) and similar specificity (93.8%) (AUC, 0.941). IgA to insect-derived EBNA1 FL had a higher 90% sensitivity, but lower 91.7% specificity (AUC, 0.940). Combining EBNA1 FL and dGAr results showed that subjects positive for both proteins had a 243.67 odds ratio for NPC incidence compared to double-negative scores. ConclusionThis study demonstrated the efficacy of EBNA1 SeroStrip-HT for NPC risk assessment and stratification in high- and intermediate-risk populations, yielding high accuracy and a 12-fold increased throughput over the prototype. The insect system was appropriate for large-scale production of purified EBNA1. Larger, geographically diverse cohorts are warranted to confirm these results, especially in low-incidence populations.

10
One Health genomics of Acinetobacter baumannii reveals sector-specific lineages and permeable ecological barriers

Plantade, J.; Escobar, C.; Godeux, A.-S.; Poire, L.; Andre, A.; Deromelaere, V.; Cassier, P.; Rasigade, J.-P.; Nazaret, S.; Coluzzi, C.; Venner, S.; Laaberki, M.-H.; Charpentier, X.

2026-04-11 infectious diseases 10.64898/2026.04.09.26350516 medRxiv
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Acinetobacter baumannii is a major cause of severe hospital-acquired infections, with a steadily increasing global prevalence driven by a few clinically adapted lineages. Animals and natural environments also harbor A. baumannii populations, but assessing their connections to clinical lineages is limited by sparse genomic data and a lack of integrated sampling. We conducted a local One Health genomic epidemiology study, sampling, isolating, sequencing, and characterizing several hundred A. baumannii isolates from clinical, animal, and environmental contexts. Within a geographically restricted area, we recovered several globally distributed clinical lineages (international clones, ICs), as well as livestock- and environment-associated lineages shared across Europe, highlighting widespread dissemination beyond clinical settings. Isolates closely related to the emerging clinical lineage IC11 were found in livestock, but no other clinically associated lineages were detected outside clinical contexts. Among these, the epidemic superlineage IC2 was identified in both human and veterinary clinical settings, indicating that similar practices in human and animal medicine select for closely related opportunistic pathogens. We found that hospitals host distinct, antibiotic-sensitive endemic populations capable of causing infection. These populations belong to a diversifying clade spanning clinical and environmental contexts and carry a high load of insertion sequences. Strong plasmid conservation further suggests frequent horizontal gene transfer across ecological compartments. Overall, A. baumannii comprises diverse, context-adapted lineages with a high potential for global spread. Although intercontext transmission appears limited, plasmids may overcome these ecological barriers. Our findings underscore the need for integrated One Health surveillance to better understand transmission pathways and limit the emergence of clinically adapted strains.

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OCA-B/Pou2af1 Expression in T Cells Promotes PD-1 Blockade-Induced Autoimmunity but is Dispensable for Anti-Tumor Immunity

Du, J.; Manna, A. K.; Medina-Serpas, M. A.; Hughes, E. P.; Bisoma, P.; Evason, K. J.; Young, A.; Wilson, W. D.; Brusko, T.; Farahat, A. A.; Tantin, D.

2026-04-16 immunology 10.1101/2025.10.22.683978 medRxiv
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The transcription coregulator OCA-B promotes CD4+ T cell memory recall responses and autoimmunity. OCA-B T cell deletion prevents spontaneous type-1 diabetes (T1D) onset in non-obese diabetic (NOD) mice and blunts T1D in a subset of more aggressive models. However, the role of OCA-B in diabetes induced by treatment with immune checkpoint inhibitors (ICIs), and the role of OCA-B in the control of tumors with and without ICI treatment, has not been studied. Here we show that islet and pancreatic lymph node T cells from T1D individuals express measurable POU2AF1 mRNA. Deletion of OCA-B in T cells fully insulates 8-week-old non-obese diabetic (NOD) mice against ICI-induced diabetes and partially protects 12-week-old mice. Salivary and lacrimal gland infiltration and inflammation were also reduced. Protection was associated with a block in the differentiation of progenitor exhausted CD8+ T cells (TPEX) into terminally exhausted CD8+ T cells (TEX). We show that OCA-B T cell loss preserves anti-tumor immune responses following PD-1 blockade in different tumors and mouse strains. These findings point to a potential therapeutic window in which pharmaceuticals targeting OCA-B could be used to block the emergence of both spontaneous and ICI-induced autoimmunity while sparing anti-tumor immunity. We develop first-in-class small molecule inhibitors of Oct1/OCA-B transcription complexes and show that administration into NOD mice also blocks diabetes emergence following PD-1 blockade. These results identify OCA-B as a promising therapeutic target for the prevention of autoimmunity and immune-related adverse events (irAEs).

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Establishment of Contextually Appropriate Cut Offs for Orthopoxvirus Serologic Assays in an Mpox-Endemic Setting

Frederick, C.; Merritt, S.; Halbrook, M.; Mukadi, P.; Anta, Y.; Kompany-Kisenzele, J. P.; Tambu, M.; Makangara-Cigolo, J.-C.; Hasivirwe Vakaniaki, E.; Kenye, M.; Lunyanga, L.; Kacita, C.; Kalonji, T.; Kinanga, C.; Linsuke, S.; Hensley, L. E.; Bogoch, I. I.; Shaw, S. Y.; Hoff, N. A.; Mbala-Kingebeni, P.; Rimoin, A. W.; Kindrachuk, J.

2026-04-14 infectious diseases 10.64898/2026.04.10.26350607 medRxiv
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Mpox virus (MPXV) gained increased attention following the declaration of two Public Health Emergencies of International Concern (PHEICs) in 2022 and 2024. The rapid spread of MPXV and the increase in human-to-human transmission highlighted the need for improved diagnostic tools for characterizing infection patterns and transmission dynamics. While PCR is effective for detecting active infections, serological approaches can help identify previous or asymptomatic infections and support retrospective surveillance. However, many serological assays developed during recent outbreaks have not been evaluated in endemic settings such as the Democratic Republic of the Congo (DRC). This study aims to define antigen-specific serological cutoff values to differentiate MPXV-seroreactive individuals from those with other orthopoxvirus (OPXV) exposure or different vaccination histories, specifically for use in the DRC. Here, we analyzed 134 individuals, divided into six distinct cohorts with different exposures. Serum samples were tested using Mesoscale Discovery (MSD) to screen for five MPXV and vaccinia virus (VACV) orthologous antigens: A29L/A27L, A35R/A33R, B6R/B5R, E8L/D8L, and M1R/L1R. Receiver operating characteristic (ROC) analysis identified the best-performing antigens and established seroreactivity cutoff values. A binary composite rule was also evaluated to improve the classification of these results. We identified three MPXV antigens, E8L (cut-off=12.33 AU/mL), A35R (cut-off=5.22 AU/mL), and B6R (cut-off=9.77 AU/mL), that showed the strongest discriminatory performance in the dataset. Collectively, these three antigens form a significant panel that demonstrated clear separation between our mpox survivor cohort and other OPXV-exposed individuals.

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SARS-CoV-2 neutralising antibody profiles reveal variant specific antibody dynamics and regional differences in infection histories in Malawi

McCormack, M. J.; Banda, L.; Kasenda, S.; Hughes, E. C.; Crampin, A. C.; Amoah, A. S.; Read, J. M.; Ho, A.; Willett, B. J.; Hay, J. A.

2026-04-17 infectious diseases 10.64898/2026.04.16.26351029 medRxiv
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Serological data provide important insights into SARS-CoV-2 transmission and immunity, particularly in regions with limited routine surveillance such as sub-Saharan Africa. However, antibody waning and boosting following reinfection or vaccination remain poorly characterised, complicating interpretation of serological measurements. Improved understanding of these dynamics is critical for accurate epidemiological inference. Modelling longitudinal serological data provides a means to quantify antibody kinetics and reconstruct infection histories. We analysed 15,679 neutralising antibody (nAb) titres from 1,675 unvaccinated, HIV-uninfected participants in urban (Lilongwe) and rural (Karonga) Malawi (February 2021 - April 2022). NAb titres against ancestral B.1, Beta, Delta, and Omicron (BA.1/BA.2) viruses were measured using an HIV-based SARS-CoV-2 pseudotyped virus neutralisation assay. A multi-level Bayesian model was used to reconstruct infection histories and antibody kinetics. The model identified 429 infections (95% credible interval 417-441), including 39 (9.1%) that had not been identified by traditional seroconversion-based thresholds. Antibody levels waned rapidly, with 48% (0.403-0.560) of the acute boost remaining after three months and only 5% (0.027-0.098) after one year. Pre-Omicron infections generated stronger antibody boosts than Omicron infections. Responses varied, with individuals clustering into low and high responders. Cross-reactive responses extended across substantial antigenic distances - Omicron infections induced broader immunity. Seroincidence was higher in Lilongwe than in Karonga (0.41 vs. 0.27 infections per person per three months), driven by the early 2022 Omicron wave. Reinfections were common, particularly among adults and urban residents. SARS-CoV-2 nAb responses following infection were heterogeneous and declined rapidly. This rapid waning underscores the importance of vaccination for sustained protection, while cross-reactivity suggests only partial immunity from prior variants. Identifying reinfections is essential for understanding transmission and finding populations at higher repeat infection risk, particularly where routine surveillance is limited.

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Inactivating PLEKHA6 Mutations Cause Idiopathic Hypogonadotropic Hypogonadism Through Impaired Kisspeptin Secretion

Topaloglu, A. K.; Plummer, L.; Su, C.-W.; Kotan, L. D.; Celmeli, G.; Simsek, E.; Zhao, Y.; Stamou, M.; Anik, A.; Döger, E.; Altıncık, S. A.; Mengen, E.; Koc, A. F.; Akkus, G.; Balasubramanian, R.; Turan, I.; Seminara, S. B.; Yuksel, B.

2026-04-13 pediatrics 10.64898/2026.04.10.26349358 medRxiv
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PurposeIdiopathic hypogonadotropic hypogonadism (IHH) is characterized by impaired reproductive maturation, and approximately half of all cases lack an identified genetic cause. We investigated the genetic basis of IHH in two large cohorts to identify novel disease-causing genes. MethodsWe analyzed exome and genome sequencing data from 1,822 patients with IHH from two independent cohorts. Rare variants were filtered using pedigree-informed inheritance models. PLEKHA6 expression in the postmortem human hypothalamus were tested at the mRNA and protein level. Functional studies assessed kisspeptin secretion in cell-based assays. ResultsWe identified 18 distinct PLEKHA6 variants in 24 patients from 20 unrelated families (1.3% of cohort). Variants segregated with disease under autosomal recessive and autosomal dominant (with variable penetrance) inheritance patterns. PLEKHA6 was robustly expressed in the hypothalamus and showed clear colocalization with neurokinin B, which served as the marker for the GnRH pulse generator. Functional studies demonstrated that patient variants significantly impaired kisspeptin secretion. ConclusionPLEKHA6 is a novel IHH gene and the first reported regulator of kisspeptin secretion from the kisspeptin-neurokinin B-dynorphin (KNDy) neurons, which have recently been established as the GnRH pulse generator. These findings establish impaired kisspeptin release as a new disease mechanism in IHH and highlight the critical role of neuropeptide trafficking in reproductive function.

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Clinical mechanism of ribavirin action in Hepatitis C treatment: insights from the STOPHCV-1 randomised trial

Moradi Marjaneh, M.; Badhan, A.; Chai, H.; Hadfield, O.; Chen, Y.; Wang, Z.; Thomson, E. C.; Taylor, G. P.; Walker, A. S.; Ansari, M. A.; Barnes, E.; Cooke, G. S.

2026-04-15 infectious diseases 10.64898/2026.04.14.26350846 medRxiv
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Background: Ribavirin is a guanosine analogue with clinical antiviral activity against a range of RNA viruses including hepatitis C virus (HCV), respiratory syncytial virus and Lassa virus. Several potential mechanisms of action have been proposed, but there is limited data supporting them clinically. Methods: We studied 196 HCV-infected participants from a trial of short-course directly antiviral therapy (STOPHCV-1) which included a factorial randomisation to ribavirin versus no ribavirin. Deep sequencing of the HCV genome was performed on samples with detectable viremia from three time-points: baseline (n = 191), day 3 of treatment (n = 25) and post-treatment failure (n = 47). Results: Ribavirin exposure significantly increased total mutational load at treatment failure (P = 0.0065) and enriched classical ribavirin-associated transitions, including G->A (P = 0.026) and C[->]U (P = 0.004), along with other key changes including A->G (P = 0.005), U->C (P = 0.023), C->G (P = 0.010), and U->A (P = 0.026). The resulting mutational signature was broad, not dominated by G-related changes. Region-specific analyses demonstrated this increase was broadly distributed across the viral genome, without strong evidence for protection of specific regions. Non-synonymous to synonymous mutation ratios (dN/dS) rose at day 3 (P = 5.5e-5) before declining at failure (P = 8.5e-7), with trends toward higher dN/dS in the ribavirin group at day 3 (P = 0.06). Conclusions: Ribavirin acts as a potent in vivo mutagen, driving viral populations toward genome-wide diversity rather than selecting a few highly fit drug-resistant clones. These findings support an error-catastrophe model.

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Uncovering the mechanisms of clinically-relevant altered antibiotic responses of Staphylococcus aureus under wound infection-mimetic conditions

Rieger, C. D.; Molaeitabari, A.; Dahms, T. E. S.; El-Halfawy, O. M.

2026-04-17 microbiology 10.64898/2025.12.22.696073 medRxiv
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Standard in vitro antimicrobial susceptibility testing (AST) using Mueller-Hinton broth (MHB) does not reflect infection-site conditions, and its results often do not correlate with therapeutic outcomes. Here, we compared the antibiotic susceptibility of methicillin-resistant Staphylococcus aureus (MRSA), a common chronic wound pathogen, in simulated wound fluid (SWF) resembling wound exudate versus MHB, revealing discordant AST results across six of nine tested antibiotic classes. The most significant were 128-fold increased resistance to tetracyclines and 256-fold sensitization to {beta}-lactams in SWF. Tetracycline resistance was mediated by MntC, an extracellular manganese-binding protein, whereas {beta}-lactam sensitization was driven by cell envelope remodelling in SWF. Galleria mellonella wound infection results matched the SWF susceptibility phenotypes, suggesting SWF better predicts in vivo wound infection therapeutic outcomes. These comprehensive phenotypic and mechanistic insights into MRSA antibiotic responses under wound-infection-mimetic conditions with direct in vivo validation identify a potential new antibiotic adjuvant target and may guide improved antibiotic therapy for MRSA wound infections.

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Combined Effects of Severe Immunocompromise and Prolonged Virus Shedding on Within-Host SARS-CoV-2 Evolution in COVID-19

Hirata, Y.; Takahashi, K.; Iwamoto, N.; Dam Jeong, Y.; Miyamoto, S.; Kawasaki, J.; Mine, S.; Iida, S.; Saito, S.; Ainai, A.; Kanno, T.; Katano, H.; Sasaki, N.; Horiba, K.; Ishikane, M.; Kamegai, K.; Harrison, M. T.; Itoh, N.; Akazawa, N.; Okumura, N.; Haraguchi, M.; Sakoh, T.; Morishima, M.; Araoka, H.; Uchida, N.; Hase, R.; Marumo, Y.; Adachi, T.; Matsue, K.; Saito, T.; Ohmagari, N.; Iwami, S.; Suzuki, T.

2026-04-17 infectious diseases 10.64898/2026.04.14.26350918 medRxiv
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Background: Prolonged SARS-CoV-2 infection in immunocompromised individuals may accelerate virus evolution within the host, raising concerns about the virus evading immunity, developing resistance, and forming novel variants of concern. However, the determinants and public health implications of within-host viral evolution in this population remain incompletely understood. Methods: We performed longitudinal analyses of SARS-CoV-2 genomes from 91 patients with COVID-19 who were classified as being severely or moderately immunocompromised. Using serial measurements of viral RNA loads and infectious titers, we modeled the shedding dynamics of the virus and stratified the infected cases by upper respiratory virus shedding duration to assess associations with within-host evolutionary dynamics. Results: Shedding modeling identified two profiles of shedding duration: intermediate and long. The long shedding profile (shedding lasting >21 days) was found in 14.8% of moderately immunocompromised cases and 72.1% of severely immunocompromised cases. Frequent single-nucleotide variants accumulated specifically in severely immunocompromised individuals with the long shedding phenotype, correlating positively with shedding duration. By contrast, mutations remained limited in moderately immunocompromised individuals with the long shedding phenotype and in severely immunocompromised individuals with the intermediate shedding phenotype. We identified mutations in the spike receptor-binding domain associated with monoclonal antibody resistance; however, we found no fitness-enhancing mutations for inter-host transmission, and antiviral drug resistance mutations were rare. Instead, mutations were introduced frequently and randomly across the entire viral genome. Conclusions: Prolonged upper respiratory virus shedding exceeding 21 days combined with severe immunocompromise is a risk factor of the accumulation of within-host SARS-CoV-2 mutations. Although no variants of concern emerged, the introduction of genome-wide random mutations suggests that the risk for novel variant generation cannot be excluded. These findings highlight the need for intensive antiviral strategies to limit shedding duration to less than 21 days in severely immunocompromised patients, and for immunological investigations to elucidate the host factors underlying residual shedding control in those who achieve clearance within this threshold.

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Comparable safety and humoral immunogenicity of delayed versus delayed fractional boosting with blood-stage malaria RH5.1/Matrix-M vaccine

Holliday, K.; Nielsen, C. M.; Roberts, T. W.; Baker, E. C.; Marshall, B.; Jarman, C.; Odongo, I.; Salkeld, J.; Diouf, A.; Marchevsky, N. G.; Ashfield, R.; King, L. D. W.; Cowan, R. E.; Lata, P.; Nugent, F. L.; Cho, J.-S.; Carnot, C.; Long, C. A.; Hope, P.; Schutter, J.; Kay, L.; Winks, T.; Skinner, K.; Silk, S. E.; Draper, S. J.; Minassian, A. M.; Payne, R. O.

2026-04-11 infectious diseases 10.64898/2026.04.10.26348898 medRxiv
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An efficacious blood-stage malaria vaccine would serve as a highly useful public health tool alongside licensed vaccines targeting the pre-erythrocytic life cycle stage of the Plasmodium falciparum parasite. RH5 is the leading blood-stage malaria vaccine candidate antigen due to its highly-conserved sequence and non-redundant role in merozoite invasion of red blood cells. Following encouraging immunogenicity data in UK and Tanzanian Phase Ia/b vaccine trials, RH5-based vaccines have progressed to Phase IIb evaluation in Burkina Faso in recent years. Here, we report a Phase Ia clinical trial in malaria-naive UK adults to assess the safety and immunogenicity of the malaria vaccine candidate RH5.1 soluble protein with Matrix-M adjuvant using two different booster dosing regimens: 10-10-10 micrograms versus 50-50-10 micrograms RH5.1, both delivered in a 0-1-6-month schedule with 50 micrograms Matrix-M adjuvant per dose (ClinicalTrials.gov NCT06141057). A total of n=24 participants were recruited to this study, with n=23 completing all follow-up visits through to 1 year following final vaccination. The RH5.1/Matrix-M formulation was well-tolerated in this population, with injection site pain, myalgia and fatigue being the most commonly reported symptoms up to 7 days post-vaccination. There were no serious adverse events, adverse events of special interest, or suspected unexpected serious adverse reactions reported over the course of the trial. Both vaccination regimens were similarly immunogenic; no differences were observed in peak anti-RH5.1 serum IgG concentrations, in vitro functional anti-parasitic activity, avidity, or durability. Our findings build on other observations from clinical trials of adjuvanted RH5.1 indicating that humoral immunogenicity can be enhanced by delaying the final booster vaccination, but that there is limited impact of fractionation of the final dose. These insights can help to guide the next steps of multi-antigen, multi-stage malaria vaccine development in malaria-endemic settings.

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Years Lived without Chronic Diseases after Statutory Retirement - A Register Linkage Follow-up Study in Finland 2000-2021

Pietilainen, O.; Salonsalmi, A.; Rahkonen, O.; Lahelma, E.; Lallukka, T.

2026-04-13 public and global health 10.64898/2026.04.12.26348889 medRxiv
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Objectives: Longer lifespans lead to longer time on retirement, despite the efforts to raise the retirement age. Therefore, it is important to study how the retirement years can be spent without diseases. This study examined socioeconomic and sociodemographic differences in healthy years spent on retirement. Methods: We followed a cohort of retired Finnish municipal employees (N=4231, average follow-up 15.4 years) on national administrative registers for major chronic diseases: cancer, coronary heart disease, cerebrovascular disease, diabetes, asthma or chronic obstructive pulmonary disease, dementia, mental disorders, and alcohol-related disorders. Median healthy years on retirement and age at first occurrence of illness (ICD-10 and ATC-based) in each combination of sex, occupational class, and age of retirement were predicted using Royston-Parmar models. Prevalence rates for each diagnostic group were calculated. Results: Most healthy years on retirement were spent by women having worked in semi-professional jobs who retired at age 60-62 (median predicted healthy years 11.6, 95% CI 10.4-12.7). The least healthy years on retirement were spent by men having worked in routine non-manual jobs who retired after age 62 (median predicted healthy years 6.5, 95% CI 4.4-9.5). Diabetes was slightly more common among lower occupational class women, and dementia among manual working women having retired at age 60-62. Discussion: Healthy years on retirement are not enjoyed equally by women and men and those who retire early or later. Policies aiming to increase the retirement age should consider the effects of these gaps on retirees and the equitability of those effects.

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Policy Levers of HIV Control: Targeted Service Coverage, Financial Protection, and Estimated New HIV Infections in Southeast Asia, 2013-2022

Hung, J.; Smith, A.

2026-04-13 public and global health 10.64898/2026.04.11.26350590 medRxiv
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The global ambition to end the human immunodeficiency virus (HIV) epidemic requires understanding which system-level policy levers, enacted under the framework of Universal Health Coverage (UHC), are most effective in achieving both transmission reduction and diagnostic coverage. This study addresses an important evidence gap by quantifying the within-country association between measurable UHC policy indicators and the estimated rate of new HIV infections across nine Southeast Asian countries between 2013 and 2022. Employing a Fixed-Effects panel data methodology, the analysis controls for time-invariant national heterogeneity, ensuring reliable estimates of policy impact. We found that marginal changes in total current health expenditure (CHE) as a percentage of gross domestic product (GDP) were not statistically significantly associated with changes in HIV incidence. However, increases in the UHC Infectious Disease Service Coverage Index were statistically significantly associated with concurrent reductions in HIV incidence (p < 0.001), suggesting the efficacy of targeted service implementation as the principal driver of curbing new HIV infections. In addition, the UHC Reproductive, Maternal, Newborn, and Child Health Service Coverage Index exhibited a statistically significant positive association with changes in HIV incidence (p < 0.01), which is interpreted as a vital surveillance artefact resulting from expanded detection and reporting of previously undiagnosed HIV cases. Furthermore, out-of-pocket (OOP) health expenditure as a percentage of CHE showed a counter-intuitive negative association with changes in HIV incidence (p < 0.01), suggesting this metric primarily shows ongoing indirect cost burdens on the established patient cohort, or, alternatively, presents a diagnostic access barrier that results in lower case finding. These findings suggest that policymakers should prioritise investment in targeted infectious disease service efficacy over aggregate fiscal commitment and utilise integrated sexual health platforms for strengthened HIV surveillance and case identification.